# Copyright 2021 RangiLyu.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from torch.nn.parallel import DistributedDataParallel

from .scatter_gather import scatter_kwargs


class DDP(DistributedDataParallel):
    def __init__(self, batchsize, **kwargs):
        self.batchsize = batchsize
        super(DDP, self).__init__(**kwargs)

    def scatter(self, inputs, kwargs, device_ids):
        return scatter_kwargs(
            inputs, kwargs, device_ids, dim=self.dim, chunk_sizes=[self.batchsize]
        )
